1. Field of the Invention
This invention concerns liquid level indicator devices and more particularly is concerned with liquid level indicators which provide a visual indication of the level of liquid enclosed in movably mounted tanks such as rinse aid dispensing tanks mounted within the inner and outer door of a front loading dishwasher, in which the tank assumes horizontal and vertical positions as the door is opened and closed.
2. Background of the Invention
It is common practice to mount detergent or rinse aid dispensing tanks within the space between the outer and inner door panels of modern-day dishwashing machines. Since such liquids need only be added occasionally, a need exists to conveniently determine the liquid level. While many relatively complex liquid level indicating devices could theoretically provide such a ready indication, the cost considerations for such applications precludes use of any but the simplest devices.
The design of such a device is complicated by the mounting of the tank within the opaque structure defined by the inner and outer dishwasher door panels, as well as by the movable position of the dispenser tank as the door is opened and closed.
The position of the tank within the door creates difficulties since any viewing device which was attempted to be inserted within the tank which would depend on the ambient light within the tank, would necessarily produce poor results due to the low light level existing within the space between the opaque door panels. Such an approach is described in U.S. Pat. No. 3,152,723. The need to extend a viewing device into the tank has been heretofore required by the nature of the installation, i.e., the level cannot be viewed with the door closed since it would be objectionable for aesthetic reasons to have an exteriorly mounted level indicator. On the other hand, the liquid retreats from the tank wall adjacent the inner panel upon opening the dishwasher door, preventing direct sighting of the tank contents through an opening in the inner panel.
Since the dispenser tanks are typically checked for the proper liquid level when the dishwasher door is in the open position, the tanks are then in the horizontal position usually presenting the greatest sidewall area to containment of the fluid and the depth is relatively slight, even though a significant quantity of liquid may remain which makes the level difficult to gauge.
It should be noted that an indication of the relative level at all times is not really required, i.e., only when the tank level approaches empty would an indication be necessary.
Accordingly, it is an object of the present invention to provide a simple, low cost liquid level indicator arrangement for providing a visual indication of the liquid level in a movably mounted tank above or below a predetermined minimum level.
It is another object of the present invention to provide such a liquid level indicator which is adapted to determine the level of liquid in a tank installed within an opaque enclosing structure.
It is yet another object of the present invention to provide such a liquid level indicator which will provide an indication of the level of the liquid within the tank when it is in a vertical or dispensing position with the indicator being viewed with the tank disposed in a horizontal position.
It is still another object of the present invention to provide such a low cost liquid level indicator particularly adapted for door mounted rinse aid tank dispensers for dishwashers which will provide visual indication when the level of the rinse aid liquid in the tank declines below a predetermined level.
A further object of the present invention is to provide such an indicator apparatus showing a visual indication of the level which allows the liquid level within the tank to be visually indicated while the tank is in the door open, horizontal position at a portion of the tank which the liquid retreats without depending on the ambient light level within the tank.